Dobby mechanism for looms



Feb. 26, 1929. 1,703,471

c. D. BROWN 1 DOBBY MECHANISM FOR LOOMS Filed Feb. 14, 1928 2Sheets-Sheet 2 Inventor. Carl D. Brown byiuad wkw Patented Feb. 26,1929.

UNITED STATES 1,703,471 PATENT OFFICE.

CARL 1). BROWN, OF HOPEDALE, MASSACHUSETTS, ASSIGNOR T DRAPEB CORPORA-TION, 0F HOPEDALE, MASSACHUSETTS, A CORPORATION OF MAINE.

DOBBY MECHANISM FOR LOOMS.

Application filed February 14, 1928. Serial No. 254,303.

This invention relates to the'control of a pattern mechanism for a loomandmore particularly for such a pattern mechanism as employed inconnection with a loom dobby. In certain types of such mechanism thepattern cylinder, which usually also comprises a pattern chain carriedthereby, is driven by; a driving shaft and this drlvmg shalt has...

journalled thereon a constantly driven element, such, for example, as asprocket wheel,

the sprocket wheel, is rotating idly onthe shaft and thus has a constanttendency to r0- tate the shaft and therewith the pattern cylinder. Whensuch undesired rotation takes place the pattern is shifted, destroyingthe proper repeat, and the goods being woven are spoiled. To preventthis it has been common heretofore to provide some such mechanism as anotched diskon the shaft with a spring pressed roller engaging thisdisk. Such a mechanism, however, acts to produce a drag on the mainshaft when it is rotating and driving the usual pattern cylinder, thusresulting in an unnecessary expenditure of power and wear of the parts.i v

The present invention has for its ohiect to provide construction inwhich, when the constantly driven element is unclntched from the drivingshaft, the driving shaft will sinmltaneously be locked against rotationso that the continued idle rotation of the driven element on theshaftcannot act to, effect undesired rotation of the shaft andconsequently of the pattern cylinder. p

The further object of the invention is to provide a constructionforsecuring thisre sult which shall be inherently incapable of producingdrag or retardation of the'driving shaft when it is being driven by theconstantly driven element to effect the rotation of the patterncylinder. 1

These and other ob 'ectsand features of the invention will appear morefully from the accompanying description and drawingsand will beparticularly pointed out in the claims. The drawings illustrate a simpleand preferred form of the invention as applied to the pattern mechanismof an ordinary type of loom dobby. As this type of dobby mechanism iswell known and familiar to those skilled in the art and as the presentinventlon relates only to a particular feature of control, it is onlynecessary to illustrate and describe in detail those parts of themechanism With which the selected embodiment of the invention isassociated. In the drawings:

Fig. 1 is a side elevation of a portion of the dobby mechanism., i

Fig. 2 is a view in end elevation looking. toward the right of theconstruction shown inFig. 1. I

Fig. 3 is a detail in top plan view. The loom pattern mechanism hereinvselected for a disclosure of apreferred form of the invention is that ofa familiar type of loom dobby wherein the dobby indicating fingels areoperated by risers carried by a pat tern chain runningover and driven bya cylinder and wherein a multiplier chain is employed under the controlof which the pattern cylinder ceases rotation or dwells forpredetermined periods in accordance with. the character of the patternbeing woven.

In the construction illustrated, the dobby indicating fingers 1 arecontrolled by risers on a pattern chain 2 running over and driven by thecylinder 3 mounted on the shaft 4 journalled in the frame 5, This shaft4=has secured or clutched'thereto a worm wheel 6 and this worm wheel,and consetp ientlytho shaft 4;, is normally;driven by a worm 7 secured.to a shaft 8 joiirnalled in the frame and extendingtransversely of andbeneath the shaft 4. r j v A constantly driven element such as asprocket wheel 9 having a hub 10 is jour nalled on the shaft 8 and thissprocket wheel is constantly driven, as by a sprocket chain 11, from asuitable source such ning shafts of the loom. A suitahleclntch isprovided between this constantly driven element 9 and the shaft 8; Inthe construe tion illustrated the sprocket Wheel 9 is slidablelongitudinally on the shaft 8 and the cooperating clutching elements areformed by a lug 12 projecting laterally from the sprocket wheel and apolygonal collarv 13 secured at'l l to the shaft 8. It will thus be seenthat when the sprocket wheel 9 and its hub 10 is slid to the left,viewing Fig. 1, to bring the lug 12 into engagement with the collar 13,the shaft 8 will be driven and will in turn drive the as one of therunand facing'the member .15.

pattern'cylinder and when the sprocket wheel and hub are slid. to theright to disconnect the clutch, that the rotation of the shaft 8', andconsequently of the pattern cylinder, will cease, but this constantlydriven sprocket wheel with its extended hub Will continue to rotate idlyon the shaft 8.

Such a disconnection of the driven element from the shaft 8 is whattakes place when a multiplier chain is employed to enable the patterncylinder to stand still predetermined interv is for predeterminedperiods during which the pattern not to 'be changed. But it will beobserved that when this disconnection. of the driven element from theshaft takes place, the driven clen'ient, such as the sprocketwhcel, isconstantly running, and often for an extended period of time, andnecessarily with considerable friction on the shaft 8. This has aconstant tendency to rotate the shaft 8 and thereby to rotate thepattern-cylinder and shift the pattern with obvious undesirable results.

In the construction illustrated, there is provided a pair ofcooperating; locking members, one fixed on the dohby frame and the otherrotatable with the shaft. These locking members are normally unlockedandthus have no effect whatever and produce no drag or retardation ofthe driving shaft and pattern cylinder. When, however,- the clutch isdisconnected to stop the rotation of the pattern cylinder, these lockingmembers are automatically locked and remain locked so long as the clutchis disconnected and thereby prevent the undesired rotation of thedriving shaft. The fixed locking member is shown as a disk-likestructure concentric with the shaft 8 and secured to or forming a partof the frame and having in its face, near its periphery, the notch 16.The cooperating locking member is shown a dog;

.17 pivoted at 18 to a disk-like structure 15) concentric with, andsecured to the shaft 8 This disk 19 is n'orided at its periphery with anotch to guide and support the free end of the dog 17. This dogstraddles the shaft 8 and is so proportioned'as to swing by ivity on itspivot into the unlockedpos den shown in Fig. 1. A helical compressionspring 21 surrounds the shaft 8 between the hub 10 of the.

constantly driven element and the dog 17 and this spring is of such alength as to be inert when the locking elements are unlocked and theclutch is connected or with the parts in the position shown in Fig. 1lit will be seen therefore that if the constantly driven element 9 withits hub 10 he slid on the shaft 8 to disconnect the clutch elements 12and 13,. the spring 21 will be rendered. active and will force thelocking dog-ll'against the disk 15 so that the free end of the dog. willlin me-diately or during the first rotation drop into the notch 16 andthus the locking members will be locked and any rotation of the shaft 8prevented. This will continue so long as the clutch members aredisconnected. When the constantly driven element is slid in the oppositedirection and the members of the clutch are re-engaged, thespring 21will be rendered inert and the dog 17 will swing out of lockingengagement with the notch 16.

As this invention is particularly concerned with a (lobby mechanism, thecooperating" clutching elements and cooper: locking elements are undercontrol of the pattern mechanisms of the dohhy with the pa ticulez.purpose in mind, as already pointed out, of insuring that the patterncylinder which controls the dobby indicating fin.- s shall be p"wentedfrom shifting when stopped by a multiplier pattern chain and until itsmove ment is to continue. I

A multiplier chain 2 is shown running over a sprocket wheel journalledon the shaft l and driven by a ratchet wheel 24 connected thereto, whichratchet whee: is actuated by a pawl on the oscillating rocker 26 of thedobhy. A shield 27 pivoted on the shaft l and having an m 28 normallyheld depressed by spring 29 stands normally in a position such as shownin Fig, 1 and prevents the pawl in its retracting stroke from catchingthe teeth of the re and wheel 24 so that the multiplier chain standsidle.

In the construction illustrated, a bell crank lever fulcrumed on. the(lobby frame at 30 has one arm 31 resting on the multiplier chain andthe other arm 32 formed in. two parts adjustab-ly connected together bythe slot and bolt construction and having at its lower end a pin 3-1-engaging a groove in the hub 10 of the constantly driven element. Thisbell crank lever normally has the arm 31 resting; on a low point, asshown in Fl 1, of the multiplier chain and with its arm 32 holding theconstantly driven element clutched to tl, shaft 8. lever is held in thisposition by a s conneetin the arm 31 to another arm 37 pi oted at 30 andcarrying a smmith-faced detont 38 riding against the teeth in theratchet wheel 24:. The spring 29 already referred to is connected to thefree end o the arm 3'7. One of the dobby indicating lingers is vprovided with a laterally projectin arm 39 connected by a link 40 to thearm 28 of the shield 27.

This bel crank position as long as high points on the multiplier chaincome under the arm 31 and during this period although the constantlydriven element 9 is rotating on the shaft 8, that shaft is lockedagainst rotation and thus the pattern cylinder is held in the desiredposition without any danger of shifting therefrom. VJhen the patterncylinder is to continue its operation, a low point in the multiplierchain comes beneath the arm 31, allowing it to drop, and consequentlythe constantly rotating member is shifted back, the clutch members 12and 13 re-engage, the locking member 1? falls out of the notch in thelocking member 15, the shaft 8 is rotated, the pattern cylinder movesthe riser from beneath the indicating linger 39, the shield 27 is swungby the spring 29 into normal position preventing the pawl 25 fromoperating the ratchet 23 and the parts again stand in the position shownin Figs. 1 and 2. p i

In the preferred construction illustrated the high point in themultiplier chain holds the clutch elements clutched and the lockingmembers disengaged while the low point holds the clutch disengaged andthe locking members locked but the invention in its broader aspects isnot to be limited to the particular type of multiplier chain norotherwise than as required by the claims.

lhe sequence of operations which talre place in either stopping orstartingthe pattern cylinder follow each other with such rapidity thatthey may be recorded for practical purposes as occurring simultaneously.

The drag on the shaft 8 by a single idle rotaa tion of the constantlydriven element 9 is usually insufficient to rotate the shaft andconuontly but one notch 16 shown in the ring member 15 so that thelocking membors are locked within the period requii for one rotation ofthe element 9, but even this period may be shortened by increasing thenumber of notch Having thus described the invention, what is claimed asnew, and desired to be -s cured by Letters Patent, is:

1. In a loom dobby mechanism of that type wherein the drivingshaft forthe usual pattern chain is c riven by a constantly rotating el mentjournalled thereon and connected thereto and disconnected therefrom by aclutch, and wherein a multiplier chain is employed, thecombinationtherewith of normal- 1y disengaged cooperating lockingmembers, one fixedon the machine frame and the other rotatable with the driving shaft, andmeans for securing the locking engagement of said locking members duringthe period the multiplier chain is active and the clutch is unclutchedand the drlven element 1s rotating idly on the shaft, thereby to preventundesired movement of the usual pattern chain.

2. A pattern mechanism for looms comprising a pattern cylinder, adriving shaft acting when rotated to rotate the cylinder, a constantlydriven element journalled on the shaft, a clutch for connecting saiddriven element to, and disconnecting it from, the shaft, normallyunlocked means for locking the shaft against rotation, and automaticallycontrolled means for simultaneously disconnecting the clutch andeffecting the look ing of the locking means and for simultaneouslyeffecting the unlocking of the locking means and connecting the'clutchwhereby,

when the clutch is disconnected, the rotation of the driven element onthe shaft cannot act to rotate the shaft and thus shift the position ofthe pattern cylinder and, when the clutch'is connected, the shaft andtherewith the pat: tern cylinder will be rotated. a

3. In a loom pattern mechanism, a driving shaft, a constantly drivenelement journalled and longitudinally slidable on the shaft, co-.operating clutch members on the shaft and driven element connected anddisconnected by sliding the driven element on the shaft, cooperatingnormally unlocked locking members, one fixed on the frame and the otherrotatable with the shaft, a spring on the shaft extending between thedriven element and the locking member on the shaft and inert when theshaft is running and when rendered active acting to effect the lockingof the locking members, and automatically controlled means for slidingthe driven element on the shaft into unolutched position and therebyrendering the spring active to effect the locking of the locking memberswhereby the continued idle rotation of the driven element on the shaftcannot actrto givean undesired r0- tation to'the shaft. I

A pattern mechanism for a loom dobby comprising a pattern cylinder, adriving s'ha I cylirider, a constantly driven elen'ient 'journailed onthe shaft, a clutch for connect- ,acting when rotated to rotate the ingsaid driven element to, and discoir necting it from, the shaft, normallyunloclred means for locking the shaft against rotation, a multiplierpattern chain, normally lnactive means for driving the multiplier '1 Jpattern chain and means COIltlOllQCl by the pattern cylinder forsimultaneously renderlng active the driving means for the multiplierpatternchain, disconnecting the clutch and moving the locking means intolocking posi ion and after a predetermined interval controlled by themultiplier pattern chain for simultaneouslymoving the locking means intounlocking position, connecting the clutch and rendering inactive thedriving means for the multiplier pattern "chain.

In testimony whereof, I have signed my name to this specification.

CARL 1). BROWN.

